Building a future: is architectural imagination the driving force behind new technologies, or do technologies inspire architects? Elaine Knutt reports on the Building Centre's new show that says we need both approaches.(Forecast: Future City & Materials of Invention)

The architectural imagination behind many of the ideas in the Barbican's Future City. is unfettered by base considerations of what can actually be built. From the architecture-as-machine aesthetic to the organic shapes of Italian avant-garde and the Japanese metabolists, these visionary architects designed their futuristic utopias with little consideration of whether science and technology would one day allow them to be constructed.

In fact, the evidence of another ongoing exhibition--100 Years of Materials of Invention at the Building Centre (Culture May 26)--shows that these utopian visions coincided with a period of relative technological stasis. While the first half the 20th century clocked up reinforced concrete, polycarbonates and carbon fibre, the roll call of technical advances slowed in its final decades.

Instead, our ingenuity and investment as a society was directed to digital communications and the virtual world. Their impact on …